1. Technical Field
The present invention relates to an asynchronous transfer mode (ATM) exchange, and more particularly, relates to a system for multiplexing/demultiplexing an ATM interprocessor communication cell (IPC) in an ATM exchange.
2. Related Art
Generally, ATM is a specific packet-oriented transfer mode using an asynchronous time division multiplexing technique where both line switching and packet switching are unified and many pieces of information such as voice, data, and pictures are organized in fixed-sized blocks, called cells. ATM can operate as both a packet exchange system and a circuit exchange system in one transmission mode for efficiently embodying both high speed and wide band communication networks. For this reason, ATM is a target transfer mode solution for implementing a broadband integrated services digital network (B-ISDN) because it offers an effective information channel management based upon virtual path and virtual channel identifiers ("VPI" and "VCI") placed in a header of each cell which facilitates the use of a multiplex, de-multiplex and exchange of digital information, and serves to decrease the costs of broad-band communication network facilities because of its flexibility in a bandwidth distribution.
Conventionally, there are a variety of ATM switching networks. Exemplary configurations are disclosed, for example, in U.S. Pat. No. 5,189,668 for ATM Switch And ATM Multiplexer issued to Takatori et al, U.S. Pat. No. 5,119,369 for Packet Switch Communication Network Using Packet Using Virtual Channel Identifiers issued to Tanabe et al., U.S. Pat. No. 5,214,642 for ATM Switching System And Adaption Processing Apparatus issued to Kunimoto, U.S. Pat. No. 5,258,977 for Switching Network For An Asynchronous Time Division Multiplex Transmission System issued to Wolker et al., U.S. Pat. No. 5,287,349 for ATM Exchange System issued to Hyodo et al., U.S. Pat. No. 5,339,310 for Switching Apparatus For Switched Network Of Asynchronous Transfer Mode issued to Taniguchi, U.S. Pat. No. 5,499,238 for Asynchronous Transfer Mode (ATM) Multiplexing Process Device And Method Of The Broadband Integrated Service Digital Network Subscriber Access Apparatus issued to Shon, U.S. Pat. No. 5,455,820 for Output-Buffer Switch For Asynchronous Transfer Mode issued to Yamada, U.S. Pat. No. 5,513,178 for Cell Multiplexing Apparatus In ATM Network issued to Tanaka., U.S. Pat. No. 5,519,707 for Multiplexing Of Communication Services On A Virtual Service Path IN An ATM Network Or The Like issued to Subramanian et al., and U.S. Pat. No. 5,594,723 for ATM Information System And Multiplexer For Assigning And Controlling Access Time issued to Tibi. An ATM multiplexer/demultiplexer can be inserted between subscriber lines and the ATM switching network for switching ATM cells as disclosed in U.S. Pat. No. 5,448,557 for ATM Multiplexer/Demultiplexer For Use In An ATM Switching System issued to Hauber, or adjacent to the ATM switching network as disclosed in U.S. Pat. No. 5,365,519 for ATM Switching System Connectable To I/O Links Having Different Transmission Rates issued to Kozaki et al., and U.S. Pat. No. 5,623,493 for Multiplexer Demultiplexer Switching Device And Network Adapter issued to Kagemoto.
For the interprocessor communication (IPC) of an ATM exchange as disclosed, for example, in U.S. Pat. No. 5,550,978 for Multiprocessor System Having Switches For Routing Cells In Parallel Among Processors by Splitting Data Into Blocks Having Numbers Of Cells Equals To Processor Bus Width issued to Takahashi et al., however, one IPC cell transceiver is required for each processor connected to the ATM exchange. As the capacity of an ATM switch increases, the number of processors increases and consequently the number of IPC cell transceivers. Moreover, since one ATM switch port per IPC cell transceiver is needed, the number of the ATM switch ports increases. Therefore, a large number of hardware is required, and it is difficult to efficiently manage resources.